1. Field of the Invention
The present invention relates to a flow control valve, and more particularly, to a pressure-compensated flow control valve that may control a flow, and may maintain a flow to be constant by compensating for a pressure autonomously in response to a rapid change in a pressure at an entrance and exit of the valve.
2. Description of the Related Art
In general, a flow control valve is widely used in machinery utilized in all industries, for example, chemical engineering plants, power plants, vessels, aircraft, rocket engines, and the like.
A liquid propellant rocket engine refers to a flying device that obtains propulsion using the principle of action and reaction, by burning a mixture of a liquid fuel and an oxidizer in a combustion chamber, and expelling exhaust gases through a nozzle. Since the propulsion of the liquid propellant rocket engine may be adjusted readily through a valve and a pump, such a liquid propellant rocket engine is preferred over a solid propellant rocket engine. In order to adjust the propulsion of the liquid propellant rocket engine, a flow of the oxidizer and the fuel supplied to the combustion chamber may be adjusted and thus, a flow control valve may be required.
In addition, when the flow control valve is used for ground equipment, and the like, an increase in weight may be unproblematic. However, in a case of a vessel, aircraft, rocket, and the like, fuel efficiency may decrease as a weight increases. Accordingly, the lighter the valve is, the greater the fuel efficiency.
FIG. 1 is a cross-sectional view illustrating a flow control valve 1 according to a conventional art.
Referring to FIG. 1, the flow control valve 1 may include a valve body 10, a first poppet 20, a second poppet 30, a sleeve 40, a spool 50, and a guide bar 60. The valve body 10 may include a flow path 11. The first poppet 20 may be fixed in the valve body 10. An inlet 21 through which a fluid flows in may be formed on one side of the first poppet 20. The first poppet 20 may include an outflow hole 22 through which the fluid flows out to the flow path 11 of the valve body 10. The second poppet 30 may include an inflow hole 32 through which the fluid flows in from the flow path 11 of the valve body 10. The second poppet 30 may include an outlet 31 through which the fluid flows out, on the other side of the first poppet 20. The sleeve 40 may adjust an area of the outflow hole 22 by covering the outflow hole 22 of the first poppet 20 while sliding along an external surface of the first poppet 20 by an actuator. The spool 50 may be formed between the first poppet 20 and the second poppet 30 to slide along an external surface of the first poppet 20 and the second poppet 30. The spool 50 may be elastically supported by the second poppet 30. The spool 50 may adjust an area of the inflow hole 32 by covering the inflow hole 32 of the second poppet 30 while sliding by a pressure of the fluid flowing in the first poppet 20. The guide bar 60 may guide the spool 50 that slides.
The flow control valve 1 may adjust the area of the outflow hole 22, by covering a portion of the outflow hole 22 of the first poppet 20 while the sleeve 40 slides. In addition, although a pressure at an entrance or exit changes rapidly, the flow may be maintained to be constant at all times, by adjusting the area of the inflow hole 32 of the second poppet 30 by the spool 50.
However, since the conventional flow control valve 1 may need to be processed such that central axes of three parts, that is, the first poppet 20, the second poppet 30, and the spool 50, are aligned with one another exactly, manufacturing the flow control value 1 may be difficult. In particular, it may be difficult to process the spool 50 such that a sealing is guaranteed by maintaining an extremely small gap while the spool 50 moves smoothly along surfaces being in contact with the first poppet 20, the second poppet 30, and the guide bar 60.